Tunable nanoantenna based on graphene

Nanoantennas play a fundamental role in the nanotechnology due to their capabilities to confine and enhance the light through converting the localized fields to propagating electromagnetic fields, and vice versa. The characteristics of nanoantennas can be modified by carefully designing the geometric size and shape as well as choosing different materials of nanoantennas. However, the features cannot be dynamically tuned once the nanoantenna is fabricated. In the literatures, the pristine graphene has been used as a transparent electrode due to the properties of high optical transmittance and electrical conductivity. Meanwhile, due to the forbidden interband transitions by the Pauli blocking, the chemically or electrostatically doped graphene can support strong plasmonic effects particularly at the far-infrared or terahertz regime. These capabilities of dynamically modifying chemical potentials enable to fabricate controllable devices by introducing the graphene sheet.